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92 VR4, K&N filter,boost solenoid mod, installing manual boost controller soon.


Hello I wanted to get some opinons.
I am contemplating a cheap exhaust mod. Since the stock mufflers are a source of restriction ( and I cant lay down the cash for a new exhaust system), I am thinking of just having the mufflers torched off and having straight pipe put in their place. I know this is not ideal (like a stainlless mandrel bent system) but it is cheap & it should reduce back pressure and increase exhaust gas velocity, which should increase performance.... Anyone done this? How does it sound?How does the performance compare to a real exhaust system...? Will this be better than stock at least? I would not even think of doiing this on a normal car, but the turbos do provide some sound reduction. I did this a few years ago with my 86 300ZxTurbo, and it sounded great, low v8 rumble, and not obnoxioulsly loud..no tickets or anything. It did seem to help performance. Any thougths on this?
 

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Discussion Starter #2
Hello there.
Does anyone have any comments or opinions or experience with this cheap exhaust mod??

Advice is greatly appreciated as i am planning on torching my mufflers off this weekend.
 

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The Wizard Of Aaahhhhh's
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skye13000gtvr4 said:
Hello there.
Does anyone have any comments or opinions or experience with this cheap exhaust mod??

Advice is greatly appreciated as i am planning on torching my mufflers off this weekend.
Hi there. Although the stock muffler is a big restriction, cutting it off will probably be too loud. And it might sound horrible. One thing you can do to open it up some would be to gut out the precats. The precats are small catalytic convertors that are located right after the O2 sensor housings up next to the engine. If you want to go a step further, remove the main cat also and replace it with a piece of pipe. This will allow your engine to breathe alot easier.


Chris
 

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I have been in a Vr4 that had no mufflers, and it wasnt that loud. It was about as loud as my Vr4 with gutted precats, downpipe, and aftermarket exhaust. The only difference is my car sounds good and that car sounds junky. Just gut your precats and get a downpipe. The cat back is not the biggest restriction.
 

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look up sean johnson on the board (thats his user name also) he has straight pipes on his vr4. no cats, no mufflers, just resonated tips i think. its not that loud and you really can't tell that its just straight pipes. he had his made though he didn't just cut out the muffler.
 

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More Than Meets the Eye
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After the main cat it's 3". When it splits, the two pipes still flow plenty. I don't think anybody has verified a gain, at least at BPU level, with a cat-back exhaust. Lose the cats, get a downpipe, and see what happens. I like mine that way because I can still switch it to quiet when I'm trying to drive through the neighborhood at 3am.
 

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Just use a glass pack, seriously. They cost all of $20 (or less) each. Just use one or put a Y in it like Furball has. I've heard his car in person and like it more than my Flowmaster.
 

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gut the cats and cut those muffers. The car will sound like an old beat-up firebird, but the turbos will sound good!

if you run some resinated tips you should be OK.
 

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I've been meaning to ask this: Where can you get a cutout at?
I need a 3" one for some experimentation.
 

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exhaust issues

Just bought a 91 vr4 with 3" custom exhaust, not cats, no mufflers. It is pretty loud, but I'm getting used to it. Sometimes it feels nice to accelerate with audible authority. At least it doesn't sound like a civic bumblebee. Besides the deep rumble, I don't really want to spend money on it, lose the true free flow or add more weight.

But if I did want to quiet it down, what are my options?

thanks,
Darvin
 

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~Airborne all the way~
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To quite something down just a tad, place a glass pack before the exaust splits in the rear, it kinda sounds like an indy car, you still got the ruble, just not as audible
-Jess
 

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Just remove the cat and run right out of the downpipe....it'll sound like a ferrari and be loud enough to shake the car...plus you will loose some major restrictions....

I'll give you 2 hours of your exhaust that loud b/f you put the cat back on...
 

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Hey originally started this thread ( different log on name )
well I was out sick yesterday so I took some time to go to a few muffler shops. here is what happened.
I live in the San Francisco area.

Again I was wanting to get muffler cut and straight pipe on...

Shop #1-local shop. Manager says" Cut your muffler off , Why? you need the back pressure. without it you wont even get it past first gear..you'll screw your car up. I wont do it in my shop."

OK on to shop #2 a midas shop.
"If you take the muffler off you will screw your up. This car has fuel injection and the O2 sensor is programmed to read teh exhaust temp which will be affected if you just run astraight pipe.
You will run too rich and lose power. It will be so loud you will get pulled over in a minute I can put on 2 glass packs for you ...installed 100$ cheap solution, and will flow good and sound deep..."

How well do cheap glass packs flow compare to exensive muffler...

OK so my exhaust still stock and now I am confused. Does anyone know a good exhaust shop in SF/Peninsula area that will do what I tell them???
 

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~Airborne all the way~
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Both muffler shops are right, and they wont do it for if your car does screw up, you can take them to court to get them to repair the damage, and easily win. You do need some sort of back pressure (without it you will lose tourqe and your a/f mixture will run rich)
Which is why my single glasspack setup is perfect for you, thier is no reason they wouldnt do it like this. Of course you could call up your old hick buddy from high school to jerry rig something for you...
-Jess
 

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More Than Meets the Eye
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Umm, no. This has been hashed to death but the gist is that turbo cars don't need backpressure to be provided by a muffler. And, nothing you do to the exhaust, <b>especially</b> the muffler, will have an impact on the fuel mixture. o2 doesn't read temps and it doesn't care about exhaust flow.

Posts like these worry me sometimes. If you know enough about your car to mod it, be confident in what you've chosen to do. If you're tentative enough to be swayed by the opinion of a muffler welder, maybe you're not ready to mod yet.
 
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